grViz(diagram = "", engine = "dot", allow_subst = TRUE, options = NULL, width = NULL, height = NULL)dot (default), neato, circo, or twopi. For more
information see https://github.com/mdaines/viz.js#usage.htmlwidget that will
intelligently print itself into HTML in a variety of contexts
including the R console, within R Markdown documents,
and within Shiny output bindings.